Starts with the soil - Soil analysis Nutrient management planning.
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Transcript of Starts with the soil - Soil analysis Nutrient management planning.
Starts with the soil - Soil analysis
Nutrient management planning
Silage Quality1.Fermentation (pH & Ammonia N)2.Feeding value (D-Value, CP & Dry Matter)
Silage Quantity1.Tonnage required
D-value depends on stage of growth and timing of harvesting
Very high D-value >75High D-value >70Moderate D-value 65-70Low D-value <65
Seed head not visible but moving up the shoot
Seed heads fully emerged and elongated
Grass at 67 D-value
60 D Very stemmy with a dead base
Relationship between silage yield and D-value
0
2
4
6
8
10
12
24-Apr 4-May 14-May 24-May 3-Jun 13-Jun 23-Jun 3-Jul 13-Jul
Date
Yie
ld (
t D
M /
ha
)
60
65
70
75
80
D-v
alu
e
D-value Total DM yield
DM yield of digestible material
67% D
Why? To assess feed value, predicted
animal performance and the need for supplementation
To identify early the stability of the silage and possible impacts on waste and animal health
How? Wait until 6 weeks post harvest Take several cores across clamp
pH of between 3.8 and 4.2 is desirable
In the field after mowing - Respiration occurs breaking down sugars.
Plant proteins are also broken down.
In the silo during filling –sugars are converted to lactic acid in the absence of air until a pH of 3.8 – 4.2 is reached.
In silo – If pH above 4.2 then undesirable bacteria grow converting sugars to butyric acid and protein to ammonia resulting in poor quality silage.
During feed-out – if pH is above 4.2 then sugars in the presence of oxygen are converted to CO2 & heat. Yeasts & moulds also grow rapidly.
1. Sward type – PRG is better
2. Nitrogen Application
3. Stage of growth
4. Weather & Grass Dry Matter
5. Silo filling & sealing technique
Ensure sugar content of grass is high (greater than 2.5% fresh weight) by:
1.Harvesting swards with a high PRG content.
2.Applying slurry & fertiliser at correct rate & time.
3.Harvesting in bright sunny weather.4.Carry out ensilability analysis.
Indicates the potential fermentation quality by giving information on:
1.Dry matter2.Crude protein3.Water soluble carbohydrates (sugars)4.Nitrate5.Buffering Capacity
Rule of thumb – allow a day for every 2 units of Nitrogen to grow out of grass
Hence 3 bags 27%N = 81 units
81 divided by 2 units/day
41 days required between fertiliser application and cutting
Ensure silage dry matter is high by:
1.assessing % DM before harvesting.
2.harvesting grass at and/or wilting to 25 -30% DM.
Spread the herbage over as large an area as possible immediately post mowing
Max wilting period 24-30 hours
Prolonged wilting reduces digestibility
Wilting results in increased silage DM intakes
Can be used as an aid to make good silage but not a remedy for poor management
Inoculants are the main type
1. Inoculants contain one or more lactic acid bacteria and promote efficient fermentation
50mm drainage pipe
600mm
125 mm
Grass placed on top by hand
0.125mm polythene
Clean pit thoroughly
Hang plastic side sheet to ensure good seal
Spread grass over pit evenly in shallow layers (6 – 9 inches)
Roll continuously
Rapid filling is best
All silage effluent must be collected.
The tank must be checked regularly to ensure that it does not overflow or that it is not leaking.
Empty the tank regularly to prevent effluent reaching drains or watercourses
Same principles apply as with pit silage
Bales should be dense and cylindrical in shape
Wrap as soon as possible after baling
4 - 6 layers of plastic film
Wrap at the stacking area if possible
If not, move bales from the field immediately after wrapping
Oxygen will enter a bale every time it is handled
Avoid spiking if possible at any time (even before wrapping)
Section A:30 x 3 x 10 = 900m3
Plus
Section B:5 x 3 x 10 = 150m3 X 0.5 = 75 m3
Total = 900 + 75 = 975m3
30m 5m
3m
Width of pit = 10m Assume silage is 30% Dry matter
A B
Example:
Conversion FactorsSilage Dry Matter Conversion factor
Measuring Quantity
Silo/Pit:
Length (m) x Width (m) x Height (m)
=
Volume (m3)
X
Dry Matter Conversion factor
=
Tonnes of silage
Measuring Quantity
kg/bale or t/bale
Round (unchopped) 1.3m 500 0.5
Round (chopped) 1.3m 650 0.65
Square (2.5mx1.2mx0.9m) 730 0.73
(8x4x3’)
Will vary enormously with dry matter, sward type and operator!
Silage RequirementsType of stock NoRequirement per month (t)
MonthsSilage
requirement
Spring calver 1.0
250 – 350 kg store
0.8
Calves 0.3
Ewes 0.15
Total silage required
Cut silage around 50% ear emergence to
optimise yield and quality
Allow 2 units N/day from sowing to cutting
Don’t overwilt – 30 hours max
Seal silo carefully
Handle bales carefully
Do a budget before winter
The amount of grass grown depends on many factors
1.Soil temperature (>6° C)2.Light 3.Water4.Nutrient availability5.Grass type/breed
At peak growth there is a new leaf every 4-5 days (May)
Peak growth all 3 leaves replaced in 2-3 weeks
Best time to graze is at 2 ½ to 3 leaves
4 main grazing systems used
1.Set stocking
2.Rotational grazing
3.Strip grazing
4.Paddock grazing
Set stocking Rotational
Paddock grazing
Animals have unrestricted access over a wide area throughout the grazing season
Pros ConsLow management input Lower grass yield
Low capital cost (1 drinking trough, external fence)
Difficult to manage and maintain grass quality and height
Can work well if sward height maintained at correct level
Uneven manure distribution
Lower utilisation due to trampling
Weeds allowed to build up
Animals move around a small number of fields based on sward height or after a certain number of days
Pros ConsHigher production than set stocking
More fencing required
Allows pasture to rest and recover
Extra drinking troughs needed
Can extend the grazing season
Grass production and utilisation not optimum
More even distribution of manure
Animals given a new allocation of grass each day by mean of electric fence
Pros ConsUseful when excess of grass at points in the year
Labour intensive. Fence needs moved each day
Good utilisation of grass – very little trampling or spoiling of grass
Water availability a problem
Very good for forage crops like kale and rape
Not ideal as cattle are usually allowed back over previous days grazings
Hampers re-growth
Can lead to trampling along fence line
Animals are moved frequently through a series of paddocks based on measured grass heights or grass covers
Pros ConsHighest grass production and use
Initial cost of fencing and water troughs
High quality grass & higher stocking rates
More intensive management – skill required
More even manure distribution
Requires careful monitoring
Can extend grazing season
Allows for excess grass to be cut out as silage (bales)
Quieter/more manageable stock?
System Annual Yield
(t DM/ha)
Utilisation
(%)
Usable yield
(t DM/ha)
% increase
Set stocking
8.5 50 4.3
Rotational
10.2 65 6.6 56%
Paddock 10.2 80 8.2 92%
To be continued!